As the communication system installed in a vehicle, a communication system has been proposed in which a plurality of ECU (electronic control units) that control electric devices installed in a vehicle are connected to shared communication lines and communicate with each other (see JP 2009-105828A, for example). In this communication system, control processing for linking a plurality of electric devices is realized by communication between the plurality of ECUs.
In a conventional communication system as disclosed in JP 2009-105828A, if one of the ECUs goes out of control and repeatedly transmits data at short time intervals, this ECU may fully occupy a shared communication line. In this case, the other ECUs that are connected to this shared communication line cannot perform communication.
The present invention has been achieved in light of such issues and an object of the present invention is to provide a power supply control apparatus and a power supply control method according to which it is possible to prevent one communication apparatus (ECU) from occupying (monopolizing) a shared communication line, and to provide a communication system including the power supply control apparatus.